This.
Joining either of the factions for the final quest had me seriously thinking over and in the end - I took the (for me) most unlikely course and ended up siding with Aeldys, cause it sounded like noone would finally win and I honestly felt noone deserved to.
And by what the game made me learn about the world, Adra, the deadfire, I didnt feel bad for chosing this rather bad ending, even on my goodie-2-shoes character.
I like how certain choices lead to certain effects later in the game, for instance how you deal with Benweth will decide on where and in which state you can meet Aeldys if you start the principis final quest-series.
Or that the events at the watershapers guild can actually make you lose the opportunity to side with the Huana completely if you choose a certain path in the quest and then make a wrong choice when facing Onekaza afterwards.
I also agree on the really tough choice on which ending you choose. Weirdly enough the Valian Ending seems to be one of the better choices, as from what I grasped, the upwind to animancy this will bring - which certainly had adarker touch to it in POE 1 - will make Kith overall come closer to the power of the Engwithans than any other ending, thus making the course of Eothas' actions less of a threat somehow.
But the sheer fact that this unexpected good they can bring is rather a sideeffect of their leader's blatantly open primary motives - plain greed - made me doubt that decision. Even though I tended to believe in Castol's honesty, even when this was overshadowed when reading Beza's notes, or finding the huana in front of the VTC's office.
No need to talk about RDC, they are the borg, period.
Last time a game had me go over my choices several times were FO:NV and ofc W3, so at least to me the main plot's writing is good.
Also the character design - Xoti and Tekehu seemingly polarize people pretty damn hard- which to me is just a sign of a deeply carved out character. I ended up liking both, while hating others.
Party banter is another thing. I could really grasp why some characters ended up getting along with eachothers while others didnt.
And I can agree with Xoti in hating Pallegina.
I feel like I'll drift even further OT from here no matter what, so TL:DR, I agree with OP and REALLY like the games writing.